242 - Novel diffusion-based MRI approaches reveal high resolution details of aortic vessel wall architecture with advanced inflammatory atherosclerosis (ID 760)
Abstract
Background and Aims
Atherosclerosis is the initiated uptake of cholesterol, mainly in an esterified form cholesteryl ester (CE) present in plasma low density lipoprotein LDL. Its initial accumulation in the intima leads to disease of the entire vessel wall and damage to the structural cells and the extracellular matrix (ECM), which regulate the mechanical properties of the vessel wall. During atherosclerosis progression, the damaged the smooth muscle cells acquire inflammatory features, with detrimental effects on vessel wall structure and function. This study applied diffusion-based MRI to investigate new linkages between the plaque lipids and vascular-tissue structural properties.
Methods
Our studies were performed in a pre-clinical rabbit model of aortic atherosclerosis that replicates many of the stages and features of human plaques, including the extensive lipid deposition advanced inflamed plaques and plaque rupture (thrombosis). Imaging was performed on an 11.7T Bruker MRI (Billerica, MA).
Results
Medial SMC were strongly co-aligned aligned perpendicular to the direction of blood flow, whereas the intimal SMC and lipids had significantly lower anisotropic diffusion properties.
Conclusions
Using diffusion-based MRI methods and application of magnetic field gradients of varying orientations, diffusion measurements were made in three dimensions for analysis of vessel wall anisotropic properties. The ability to visualize 2D and 3D vessel wall diffusion properties ex vivo at high field (11.7T) gave insights into smooth muscle cell vessel wall architecture, the presence and location of CE lipids in plaques, and thrombus properties, and as validated by histology.
